(ii) The test procedures shall be as follows: (A) When the protective frame structures are not an integral part of the enclosure, the direction and point of load application for both side and rear shall be the same as specified in § 1928.52 (d) (2). (B) When the protective frame structures are an integral part of the enclosure, apply the rear load in accordance with Fig. C-14 and record L and D simultaneously. Rear load application shall be uniformly distributed on the frame structure over an area perpendicular to the load application, no greater than 160 sq. in. (1032 sq. cm.) in size with a largest dimension no greater than 27 in. (686 mm). The load shall be applied to the upper extremity of the structure at the point which is midway between the centerline of the protective enclosure and the inside of the protective structure. If no structural cross member exists at the rear of the enclosure, a substitute test beam which does not add strength to the structure may be utilized to complete this test procedure. The test shall be stopped when: (1) The strain energy absorbed by the structure is equal to or greater than the required input energy E., or; (2) Deflection of the structure exceeds the allowable deflection, (see paragraph (e) (1) (i) of this section) or; (3) The structure load limit (see Fig. C-5) occurs before the allowable deflection is reached in rear load. (C) Using data obtained in paragraph (d) (2) (iii) (B) of this section, construct the L-D diagram for rear loads as shown typically in Fig. C-5. (D) Calculate E... (E) Calculate FER... (F) When the protective frame structures are an integral part of the enclosure, apply the side load in accordance with Fig. C-13 and record L and D simultaneously. Static side load application shall be uniformly distributed on the frame over an area perpendicular to the direction of load application, and no greater than 160 sq. in. (1032 sq. cm.) in size, with a largest dimension no greater than 27 in. (686 mm). Side load application shall be at a 90 degree angle to the center line of the vehicle. The center of side load application shall be located between a point “k”, 24 in. (610 mm) forward; and point "7", 12 in. (305 mm) rearward of the seat reference point to best utilize the structural strength (see Fig. C-13). This side load shall be applied to the longitudinal side farthest from the point of rear load application. The test shall be stopped when: (1) The strain energy absorbed by the structure is equal to or greater than the required input energy E.; or (2) Deflection of the structure exceeds the allowable deflection (see paragraph (e) (1) (i) of this section); or (3) The structure load limit (see Figure C-5) occurs before the allowable deflection is reached in side load. (G) Using data obtained in paragraph (d) (2) (iii) (F) of this section construct the L-D diagram for side load as shown typically in Fig. C-5. (H) Calculate FER... (I) Calculate FERis. (3) Dynamic test procedure. (1) The following test conditions shall be met: (A) The protective enclosure and tractor shall be tested at the weight defined in § 1928.51(a). (B) The dynamic loading shall be accomplished by use of a 4410 lb. (2000 kg) weight acting as a pendulum. The impact face of the weight shall be 27±1 in. by 27±1 in. (686±25 mm by 686±25 mm) and shall be constructed so that its center of gravity is within 1 in. (25.4 mm) of its geometric center. The weight shall be suspended from a pivot point 18 to 22 ft. (5.5-6.7 m) above the point of impact on the enclosure and shall be conveniently and safely adjustable for height. (See Fig. C-6). (C) For each phase of testing, the tractor shall be restrained from moving when the dynamic load is applied. The restraining members shall have strength no less than, and elasticity no greater than that of 0.50 in. (12.7 mm) steel cable. Points of attachment of restraining members shall be located an appropriate distance behind the rear axle and in front of the front axle to provide a 15 to 30 degree angle between the restraining cable and the horizontal. For the impact from the rear, the restraining cables shall be located in the plane in which the center of gravity of the pendulum will swing, or alternatively, two sets of symmetrically located cables may be used at lateral locations on the tractor. For the impact from the side, restraining cables shall be used as shown in Figures C-15 and C-16. (D) The front and rear wheel tread stttings, where adjustable, shall be at the position nearest to halfway between the minimum and maximum settings obtainable on the vehicle. Where only two settings are obtainable, the minimum setting shall be used. The tires shall have no liquid ballast and shall be inflated to the maximum operating pressure recommended by the manufacturer. With specified tire inflation, the restraining cable shall be tightened to provide tire deflection of 6 to 8 percent of nominal tire section width. After the vehicle is properly restrained, a wooden beam no smaller than 6 x 6 in. (150 x 150 mm) cross-section shall be driven tightly against the appropriate wheels and clamped. For the test to the side, an additional wooden beam shall be placed as a prop against the wheel nearest the operator's station and shall be secured to the base so that it is held tightly against the wheel rim during impact. The length of this beam shall be chosen so that it is at an angle of 25 to 40 degrees to the horizontal when its is positioned against the wheel rim. It shall have a length 20 to 25 times its depth and width 2 to 3 times its depth. (See Figs. C-15 and C-16.) (E) Means shall be provided for indicating the maximum instantaneous deflection along the line of impact. A simple friction device is illustrated in Fig. C-4. (F) No repairs or adjustments shall .be made during the test. (G) If any cables, props, or blocking shift or break during the test, the test shall be repeated. (ii) H=Vertical height of center of gravity of 4410 lb. (2000 kg) weight in inches (H' in mm). The weight shall be pulled back so that the height of its center of gravity above the point of impact is: H=4.92+0.00190 W or (H'= 125+0.107 W'). (Fig. C-7.) = (iii) The test procedures shall be as follows: (A) The enclosure structure shall be evaluated by imposing dynamic loading from the rear followed by a load to the side on the same enclosure structure. The pendulum swinging from the height determined by paragraph (d) (3) (ii) of this section shall be used to impose the dy namic load. The position of the pendulum shall be so selected that the initial point of impact on the protective structure is in line with the arc of travel of the center of gravity of the pendulum. Where a quick release mechanism is used, it shall not influence the attitude of the block. (B) Impact at rear: The tractor shall be properly restrained in accordance with paragraphs (d) (3) (1) (C) and (d) (3) (1) (D) of this section. The tractor shall be positioned with respect to the pivot point of the pendulum so that the pendulum is 20 degrees from the vertical prior to impact as shown in Fig. C-15. The impact shall be applied to the upper extremity of the enclosure structure at the point which is midway between the center line of the enclosure structure and the inside of the protective structure. If no structural cross member exists at the rear of the enclosure structure, a substitute test beam which does not add to the strength of the structure may be utilized to complete the test procedure. (C) Impact at side: The blocking and restraining shall conform to paragraphs (d) (3) (i) (C) and (d) (3) (i) (D) of this section. The center point of impact shall be at the upper extremity of the enclosure at a 90° angle to the centerline of the vehicle and located between a point "k", 24 in. (610 mm) forward, and a point "7", 12 in. (305 mm) rearward of the seat reference point, to best utilize the structural strength. (See Fig. C-13.) The side impact shall be applied to the longitudinal side farthest from the point of rear impact. རྩྭ (4) Field upset test procedure. (1) The following test conditions shall be met. (A) The tractor shall be tested at the weight as defined in § 1928.51(a). (B) The test shall be conducted on a dry, firm soil bank. The soil in the impact area shall have an average cone index in the 0 to 6 in. (0 to 152 mm) layer of not less than 150. Cone index shall be determined in accordance with American Society of Agricultural Engineers Recommendation ASAE R313.1, Soil Cone Penetrometer (1971). The path of vehicle travel shall be 12±2 degrees to the top edge of bank. (C) An 18 in. (457 mm) high ramp as described in Fig. C-10 shall be used to assist in upsetting the vehicle to the side. 1 Copies may be obtained from American Society of Agricultural Engineers, 2950 Nils Road, St. Joseph, Michigan 49085. (D) The front and rear wheel tread settings, where adjustable, shall be at the position nearest to halfway between the minimum and maximum settings obtainable on the vehicle. Where only two settings are obtainable, the minimum setting shall be used. (ii) Field upsets shall be induced to the rear and side. (A) Rear upset shall be induced by engine power with the tractor operating in a gear to obtain 3 to 5 mph (4.8 to 8.0 km per hour) at maximum governed engine rpm, by driving forward directly up a minimum slope of 60°+5° as shown in Fig. C-11 or by an alternate equivalent 1.eans. The engine clutch may be used to and in inducing the upset. (B) To induce side upset, the tractor shall be driven under its own power along the specified path of travel at a minimum speed of 10 mph (16 km per hour), or at maximum vehicle speed if under 10 mph (16 km per hour), and over the ramp as described in paragraph (d) (4) (i) (C) of this section. (e) Performance requirements · (1) General requirements. (i) The protective enclosure structural members or other parts in the operator area may be deformed in these tests but shall not shatter or leave sharp edges exposed to the operator. They shall not encroach on a transverse plane passing through points d and f within the projected area defined by dimensions d, e, and g or on the dimensions shown in Figs. C-13, and C-14, as follows: d=2 in. (51 mm) inside of protective structure to vertical centerline of seat. e= 30 in. (762 mm) at the longitudinal centerline. f=Not greater than 4 in. (102 mm) measured forward of seat refer- 9=24 in. (610 mm) minimum. outer periphery of steering wheel. (ii) The protective structure and connecting fasteners must pass the static or dynamic tests described in paragraphs (d) (2), (d) (3), or (d) (4) of this section at a metal temperature of 0 degrees fahrenheit or below, or exhibit Charpy V-notch impact strengths as follows: 10 mm x 10 mm specimen: 8 ft.-lb. at -20° F. 10 mm x 7.5 mm specimen: 7 ft.-lb. at -20' F. 10 mm x 5 mm specimen: 5.5 ft.-lb. at -20° F. 10 mm x 2.5 mm specimen: 4 ft.-lb. at -20° F. Specimens shall be longitudinal and taken from flat stock, tubular, or structural sections before forming or welding for use in the protective enclosure. Specimens from tubular or structural sections shall be taken from the middle of the side of greatest dimension, not to include welds. (iii) Glazing shall conform to the requirements contained in Society of Automotive Engineers Standard SAE J674, Safety Glazing Materials (1963).* (iv) Two or more operator exits shall be provided and positioned to avoid the possibility of both being blocked by the same accident. (2) Static test performance requirements. In addition to meeting the requirements of paragraph (e)(1) of this section in both side and rear loads, FER. and FER.. shall be greater than 1. (3) Dynamic test performance requirements. The structural requirements will be met where the dimensions in paragraph (e) (1) of this section are adhered to in both side and rear loads. (4) Field upset test performance requirements. The requirements of paragraph (e) (1) of this section shall be met in both side and rear upsets. APPENDIX A-EMPLOYEE OPERATING 1. Securely fasten your seat belt if the tractor has a ROPS. 2. Where possible, avoid operating the tractor near ditches, embankments, and holes. 3. Reduce speed when turning, crossing slopes, and on rough, slick, or muddy surfaces. 4. Stay off slopes too steep for safe operation. 5. Watch where you are going, especially at row ends, on roads, and around trees. 6. Do not permit others to ride. 7. Operate the tractor smoothly-no jerky turns, starts, or stops. 8. Hitch only to the drawbar and hitch points recommended by tractor manufacturers. 9. When tractor is stopped, set brakes securely and use park lock if available. * Copies may be obtained from the Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, Pa. 15096. |